38 Water and the Traveller

名称：38 Water and the Traveller
内容简介：
新概念英语第四册（英音）
[al:新概念英语（四）]
[ar:MP3 同步字幕版（英音）]
[ti:Water and the Traveller]

[00:01.51]Lesson 38
[00:03.45]Water and the traveller
[00:11.95]What does this text describe?
[00:16.88]Contamination of water supplies is usually due to poor sanitation close to water sources,
[00:23.71]sewage disposal into the sources themselves, leakage of sewage into distribution systems or contamination with industrial or farm waste.
[00:34.92]Even if a piped water supply is safe at its source, it is not always safe by the time it reaches the tap.
[00:43.24]Intermittent tap-water supplies should be regarded as particularly suspect.
[00:49.68]Travellers on short trips to areas with water supplies of uncertain quality
[00:55.51]should avoid drinking tap-water, or untreated water from any other source.
[01:01.52]It is best to keep to hot drinks, bottled or canned drinks of well-known brand names-
[01:07.76]international standard of water treatment are usually followed at bottling plants.
[01:13.72]Carbonated drinks are acidic, and slightly safer.
[01:17.82]Make sure that all bottles are opened in your presence, and that their rims are clean and dry.
[01:25.14]Boiling is always a good way of treating water.
[01:28.87]Some hotels supply boiled water on request and this can be used for drinking, or for brushing teeth.
[01:36.44]Portable boiling elements that can boil small quantities of water are useful when the right voltage of electricity is available.
[01:45.31]Refuse politely any cold drink from an unknown source.
[01:50.80]Ice is only as safe as the water from which it is made,
[01:54.55]and should not be put in drinks unless it is known to be safe.
[01:59.25]Drinks can be cooled by placing them on ice rather than adding ice to them.
[02:05.33]Alcohol may be a medical disinfectant,
[02:08.62]but should not be relied upon to sterilize water.
[02:12.47]Ethanol is more effective at a concentration of 50-70 percent;
[02:18.61]below 20 per cent, its bactericidal action is negligible.
[02:24.30]Spirits labelled 95 proof contain only about 47 per cent alcohol.
[02:31.21]Beware of methylated alcohol,
[02:34.07]which is very poisonous and should never be added to drinking water.
[02:39.39]If no other safe water supply can be obtained,
[02:42.72]tap water that is too hot to touch can be left to cool and is generally safe to drink.
[02:49.73]Those planning a trip to remote areas, or intending to live in countries where drinking water is not readily available,
[02:57.06]should know about the various possible methods for making water safe.